Steam trap of the disc-type

ABSTRACT

This invention relates to a disc-type stream trap, wherein a disc valve is mounted in a chamber defined by a main body and a cover with the main body formed with an inlet port and an outlet port, and having outer and inner annular valve seats, The central portion of the disc valve is made slightly higher or the inner annular valve seat is made slightly higher than the outer seat so that the valve may maintain its closed state due to intimate contact with the valve seats, even through the valve becomes curved when exposed to steam at high temperatures and pressure at work.

llliiitnnl Mates Patent Fu iwara [72] Inventor: llfiatsuii Fujiwara, 911 Nishitani, Hiraokacho, Kakogawa-shi, I-Iyogo-ken, Japan [22] Filed: Aug. 12, 1969 [21] Appl. No.: 849,435

[51] lint. Cl ..1"ll6t 1/041 [58] lFieldl ollSearclh ..236/59,58,43; 137/183 [56] References Cited UNITED STATES PATENTS 1,163,316 12/1915 Brown ..236/59 UX FOREIGN PATENTS OR APPLICATIONS 961,765 6/1964 Great Britain ..236/59 [15] @flifiAAfi Feb. 29, 1972 1,142,176 10/1961 Germany ..236/59 Primary Examiner-William E. Wayner AttorneyMcGlew and Toren [5 7] ABSTRACT This invention relates to a disc-type stream trap, wherein a disc valve is mounted in a chamber defined by a main body and a cover with the main body formed with an inlet port and an outlet port, and having outer and inner annular valve seats, The central portion of the disc valve is made slightly higher or the inner annular valve seat is made slightly higher than the outer seat so that the valve may maintain its closed state due to intimate contact with the valve seats, even through the valve becomes curved when exposed to steam at high temperatures and pressure at work.

8 Claims, 11.1 Drawing Figures Patented Feb. 29, 1972 3,645,444

2 Sheets-Sheet l INVENTOR WHTSUW FUJI WHRH ATTORNEY f.

Patented Feb. 29, 1972 3,645,444

2 Sheets-Sheet 2 Fig. 7 Fig. 8 3- c F 2 3 c- F .2

F D E E a B D Fig. .9 Fig. /0 3 c F. 2 3 c F 2.

p D {v D B a B mvsmon KHTZSUTI FUTIWFIRB ATTORNEYS STEAM TRAP OF 'IIIIE DISC-TYPE BACKGROUND OF THE INVENTION Steam traps of the disc type have hitherto had a disadvantage in that the disc valve tends to be deformed by the upwardly directed force exerted from below by the pressure of steam on the central portion of the disc valve through the ejection port and by the downwardly directed force exerted from above by the pressure in the pressure chamber on the peripheral portion of the disc when the steam traps are used to handle steam at elevated temperature and high pressure. As a result of deformation, the disc valve becomes curved in such a manner that the central portion projects toward the pressure chamber so that the disc valve becomes convex in shape. The curvature of the disc valve is enhanced as it is heated by the steam at elevated temperature introduced through the ejection port, so that a small clearance tends to be formed between the surface of the disc valve and the inner annular valve seat. Once the clearance is formed, the disc valve cannot provide a tight seat and leakage of steam results. The leakage of steam tends to cause erosion of the inner annular valve seat radially of the disc valve which in turn causes an increase in the leakage of steam. Thus, steam traps of the disc type have hitherto had a short service life. Because of this, it has hitherto been considered impractical to use steam traps of the disc type in applications where steam at elevated temperature and high pressure is used.

SUMMARY OF THE INVENTION An object of the present invention is to provide a steam trap of the disc type of long service life which can handle steam at elevated temperature and high pressure without developing leakage of steam. The steam trap embodying this invention is constructed such that no clearance is formed between its disc valve and its outer and inner annular valve seats even if the disc valve may be curved slightly as it is distorted by heat and pressure, whereby the valve can provide a tight seat.

Other objects as well as features and advantages of the invention will become evident from consideration of the description set forth hereinafter when considered in conjunction with the accompanying drawings showing embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. I to show embodiments of a steam trap according to this invention comprising a disc valve which is ground such that its central portion has a height greater than the height of its outer marginal portion, FIG. I being a vertical sectional view of one embodiment of the steam trap in its unused state, FIGS. 2 and d'being fragmentary sectional views of the steam trap of FIG. I with its disc valve being closed and its disc valve being opened, respectively, and FIGS. 4 and 5 being fragmentary sectional views of another embodiment of the steam trap in its unused state and with its disc valve being closed respectively; and

FIGS. 6 to III show embodiments of the steam trap according to this invention comprising valve seats which are ground such that its inner annular valve seat has a height slightly greater than the height of its outer annular valve seat, FIG. 6 being a vertical sectional view of another embodiment of the steam trap in its unused state, FIGS. 7 and 8 being fragmentary sectional views of the steam trap of FIG. 6 with its disc valve being closed and its disc valve being opened respectively, and FIGS. 9 and It] being fragmentary sectional views of still another embodiment of the steam trap in its unused state and with its disc valve being closed respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will now be explained with reference to FIGS. I to 3, in which I is a main body, 2 a disc valve, and 3 a cover. A designates an inlet port, B an ejection port, C a pressure chamber, D a discharge port, E an outlet port, F an inner annular valve seat, and G an outer annular valve seat.

In operation, air or condensate is introduced into the steam trap through the inlet port A upon initiation of feeding of steam and passed to the ejection port B to open the valve as shown in FIG. 3. As the air or condensate is discharged through the discharge port I) and outlet port E, steam is introduced into the steam trap. The rate of flow of steam below the underside of the disc valve 2 is higher than the rate of flow of condensed water, so that a reduction in dynamic pressure is produced in accordance with the Bernoulli's theorem. At the same time, the static pressure of steam introduced into the pressure chamber C acts on the upper surface of the disc valve 2 to urge the same to move downwardly, whereby the disc valve 2 is closed.

I-Iereupon, the pressure within the pressure chamber acts as a valve closing force on the whole upper surface of the disc valve 2, while the pressure on inlet side from the ejection port B acts as a valve opening force concentrically on the central portion of the disc valve 2. When subjected to these forces, the disc valve 2 is deformed in such a manner that the central portion thereof becomes convexed toward the pressure chamber. The curvature of the disc valve 2 is increased by the heat of steam to which it is exposed, so that a small clearance is formed between the disc valve 2 and the inner valve seat F and steam begins to leak therethrough. In one embodiment of the present invention, the underside of the disc valve is formed in spherical shape such that its central portion has a height slightly greater than the height of its outer marginal portion. By virtue of this arrangement, the disc valve remains closed as shown in FIG. 2 even if the disc valve 2 is curved, with no clearance being formed between the disc valve 2 and the valve seats.

If condensed water is introduced again into the steam trap through the inlet port A to fill the ejection port B, the steam in the pressure chamber C is cooled and condensed as by dissipation of heat to outside through the cover 3 and its pressure is reduced. Then, the force of steam acting on the underside of the disc valve 2 from below gets the better of the force acting on the upper surface of the disc valve 2 from above, so that the disc valve 2 is opened and water is discharged This cycle of operation is repeated to discharge condensed water.

In the embodiment shown and described above, the disc valve 2 is formed such that its underside is in spherical shape and its central portion has a greater height than its outer marginal portion. Similar results can be achieved by providing a projection in the form of a concentric circle in the central portion of the disc valve 2 as shown in FIG. I. FIG. 5 shows the steam trap of FIG. 4 with its disc valve being closed.

FIGS. 6 to III show other embodiments of the invention, in which the disc valve is of the conventional form and the inner annular valve seat has a height slightly greater than the height of the outer annular valve seat according to another aspect of the present invention. In the embodiment shown in FIGS. 6 to II, the inner and outer annular valve seats are in planar form, FIG. 6 showing the steam trap in its unused state and FIGS. 7 and S showing its disc valve being closed and being opened respectively. The valve seats of the embodiment shown in FIG. 9 are in spherical form, with the inner annular valve seta having a slightly greater height than the outer annular valve seat. The embodiment of FIG. 9 can achieve similar results.

From the foregoing description, it will be appreciated that the present invention provides, in one aspect, a steam trap in which its disc valve is ground such that its central portion has a height slightly greater than the height of its outer marginal portion. In another aspect, the invention provides a steam trap in which its valve seats are ground such that the inner annular valve seat has a height slightly greater than the outer annular valve seat. The amount in which the disc valve or the valve seats are ground may vary slightly depending on the manner in which the trap is used or the pressure :and temperature it is intended to handle. The values can be obtained empirically. As a result of experiments, it has been found in the present invention that the object of the invention can be attained by providing a difference in height between the central portion and the outer marginal portion of the disc valve or between the inner annular valve seat and the outer annular valve seat which is in the range from 1/1000 to 100/1000 millimeter.

The steam trap according to this invention has many advantages. lt can handle steam at elevated temperature and high pressure without its disc valve being deformed and curved to form a clearance between the disc valve and the inner annular valve seat. This is conducive to the prevention of steam leak. Thus, no erosion of the inner annular valve seat is caused, and consequently the steam trap can have a longer service life than conventional steam traps of the same type. In addition, the invention can produce at small cost a steam trap of the disc valve type of overall small size and light weight adapted to handle steam at elevated temperature and high pressure. The invention contributes greatly to the development of industry in the field of heat control.

What is claimed is:

l. A steam trap of the disc type comprising a valve body having an inlet opening and a discharge opening spaced from the inlet opening, said valve body forming an inlet port extending from the inlet opening and a discharge port extending from the discharge opening, wall means on said valve body disposed between the inlet and discharge openings and forming an intermediate opening from said valve body, cover means mounted on said wall means and forming a closure for the intermediate opening and combining with said wall means to form a chamber, said wall means forming a first passageway connecting said inlet port and said chamber and forming an inner annular valve seat about the periphery of said first passageway at its end within said chamber, said wall means forming a second passageway connecting said discharge port and said chamber and forming an outer annular valve seat disposed about said inner annular valve seat at the end of said second passageway within said chamber so that said chamber forms a connecting passage between said inlet port and discharge port through said first and second passageways, a disc valve positioned within said chamber and arranged to form a closure across said first and second passageways by seating on said inner and outer annular valve seats and being displaceable from said valve seats to admit flow between said first and second passageways, said disc valve being flexible and having a curved configuration when it is exposed to steam at elevated temperature and high pressure so that its peripheral edge curves toward said outer annular valve seat, said disc valve being displaceable between a first position when the steam trap is not in use and a second and third position when the steam trap is in use with the second position permitting flow between said first and second passageways and the third position blocking flow between said first and second passageways, and said disc valve having a configuration in the first position so that it contacts said inner annular valve seat and about its periphery it is spaced a short distance from said outer annular valve seat forming a small clearance therebetween and when said disc valve is exposed to elevated temperature and high pressure in the third position it contacts said outer annular valve seat about its periphery and remains in intimate contact with said inner annular valve seat forming a tight seal with said inner and outer annular valve seats.

2. A steam trap of the disc type, as set forth in claim 1, characterized in that said inner annular valve seat projects into said chamber beyond said outer annular valve seat.

3. A steam trap of the disc type, as set forth in claim 2, characterized in that said inner annular valve seat projects into said chamber beyond said outer annular valve seat by 1/1000 to /1000 mm.

41. A steam trap of the disc type, as set forth in claim 2, characterized in that said inner and outer annular valve seats are each located in planes disposed in spaced-parallel relationship to the other.

5. A steam trap of the disc type, as set forth in claim 2, characterized in that said inner annular valve seat and said outer annular valve seat each have a spherical convex configuration.

6. A steam trap of the disc type, as set forth in claim 1,

characterized in that said disc valve on its side facing said inner and outer annular valve seats having a spherical configuration with its centrally disposed surface projecting outwardly beyond its peripheral surface.

7. A steam trap of the disc type, as set forth in claim 1, characterized in that said disc valve on its side facing said inner and outer annular valve seats having a centrally arranged circular shaped projection extending toward said valve seats and having its periphery extending radially outwardly beyond said inner annular valve seat and being spaced radially inwardly from said outer annular valve seat.

8. A steam trap of the disc type as claimed in claim 1 characterized in that the central portion of said disc valve has a height which is greater by 1/1000 to 100/1000 millimeter than the height of its outer marginal portion. 

1. A steam trap of the disc type comprising a valve body having an inlet opening and a discharge opening spaced from the inlet opening, said valve body forming an inlet port extending from the inlet opening and a discharge port extending from the discharge opening, wall means on said valve body disposed between the inlet and discharge openings and forming an intermediate opening from said valve body, cover means mounted on said wall means and forming a closure for the intermediate opening and combining with said wall means to form a chamber, said wall means forming a first passageway connecting said inlet port and said chamber and forming an inner annular valve seat about the periphery of said first passageway at its end within said chamber, said wall means forming a second passageway connecting said discharge port and said chamber and forming an outer annular valve seat disposed about said inner annular valve seat at the end of said second passageway within said chamber so that said chamber forms a connecting passage between said inlet port and discharge port through said first and second passageways, a disc valve positioned within said chamber and arranged to form a closure across said first and second passageways by seating on said inner and outer annular valve seats and being displaceable from said valve seats to admit flow between said first and second passageways, said disc valve being flexible and having a curved configuration when it is exposed to steam at elevated temperature and high pressure so that its peripheral edge curves toward said outer annular valve seat, said disc valve being displaceable bEtween a first position when the steam trap is not in use and a second and third position when the steam trap is in use with the second position permitting flow between said first and second passageways and the third position blocking flow between said first and second passageways, and said disc valve having a configuration in the first position so that it contacts said inner annular valve seat and about its periphery it is spaced a short distance from said outer annular valve seat forming a small clearance therebetween and when said disc valve is exposed to elevated temperature and high pressure in the third position it contacts said outer annular valve seat about its periphery and remains in intimate contact with said inner annular valve seat forming a tight seal with said inner and outer annular valve seats.
 2. A steam trap of the disc type, as set forth in claim 1, characterized in that said inner annular valve seat projects into said chamber beyond said outer annular valve seat.
 3. A steam trap of the disc type, as set forth in claim 2, characterized in that said inner annular valve seat projects into said chamber beyond said outer annular valve seat by 1/1000 to 100/1000 mm.
 4. A steam trap of the disc type, as set forth in claim 2, characterized in that said inner and outer annular valve seats are each located in planes disposed in spaced-parallel relationship to the other.
 5. A steam trap of the disc type, as set forth in claim 2, characterized in that said inner annular valve seat and said outer annular valve seat each have a spherical convex configuration.
 6. A steam trap of the disc type, as set forth in claim 1, characterized in that said disc valve on its side facing said inner and outer annular valve seats having a spherical configuration with its centrally disposed surface projecting outwardly beyond its peripheral surface.
 7. A steam trap of the disc type, as set forth in claim 1, characterized in that said disc valve on its side facing said inner and outer annular valve seats having a centrally arranged circular shaped projection extending toward said valve seats and having its periphery extending radially outwardly beyond said inner annular valve seat and being spaced radially inwardly from said outer annular valve seat.
 8. A steam trap of the disc type as claimed in claim 1 characterized in that the central portion of said disc valve has a height which is greater by 1/1000 to 100/1000 millimeter than the height of its outer marginal portion. 